Fixed-dose pharmaceutical composition comprising rifabutin, clarithromycin, and clofazimine

ABSTRACT

Oral administration of a solid dosage form of the present invention comprising an effective amount of rifabutin, an effective amount of clarithromycin, an effective amount of clofazimine, and an effective amount of an absorption enhancer, is used to treat a subject suffering from, or susceptible to, Mycobacterium avium subspecies paratuberculosis infection. In an embodiment, the solid dosage form is sufficiently designed to result in a reduction in the increased metabolism of clarithromycin caused by rifabutin. In an embodiment, the solid dosage form is sufficiently designed to result in a reduction in the metabolism of rifabutin caused by clarithromycin. In an embodiment, the solid dosage form is sufficiently designed to result in a reduction in risk of a subject developing leucopenia or uveitis as a result of rifabutin.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/585,879, filed May 3, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/131,533, filed Mar. 18, 2016, which is acontinuation of U.S. patent application Ser. No. 14/271,814, filed May7, 2014, now U.S. Pat. No. 9,314,477, which is a continuation of U.S.patent application Ser. No. 13/722,395, filed Dec. 20, 2012, now U.S.Pat. No. 9,072,763 which is a continuation of U.S. patent applicationSer. No. 12/918,310, filed Nov. 29, 2010, now U.S. Pat. No. 8,343,511,which is a National Stage Entry of PCT/AU09/00129, filed Feb. 5, 2009,which claims the benefit of and priority to U.S. Provisional ApplicationSer. No. 61/065,144, filed Feb. 8, 2008, the entirety of theseapplications are hereby incorporated herein by reference.

BACKGROUND

Inflammatory bowel disease (IBD) is a disorder of unknown etiologycharacterized typically by diarrhea, cramping, abdominal pains, weightloss and rectal bleeding, tiredness, anemia, fistulae, perforations,obstruction of the bowel and frequent need for surgical intervention. Itencompasses a number of disorders including Crohn's disease, ulcerativecolitis, indeterminate colitis, microscopic colitis and collagenouscolitis. Such disorders may at times begin clinically with a more benignor milder presentation, resembling Irritable Bowel Syndrome (IBS) whichcan subsequently progress to increasing inflammation accompanying theIBS and may ultimately develop full-blown IBD. The precise causes of IBDand IBS remain unknown. However, there has been a rapidly growingevidence base that Mycobacterium avium subspecies paratuberculosis(MAP), and perhaps its various strains and sub-strains, are involved ina variety of different diseases and may play an infective role in asignificant proportion of patients with Crohn's disease and may co-existin other inflammatory bowel disorders listed above.

Accordingly, there was a need for an effective treatment of MAP-infectedIBD, and in particular Crohn's disease. U.S. Pat. No. 6,277,863 toBorody (“Borody”) describes treatment of IBD using rifabutin incombination with the macrolide clarithromycin and clofazimine. Thesewere prescribed to be ingested simultaneously but as separate tabletsand capsules. It was found that taking the capsules and tabletssimultaneously caused unwanted interactions of the medications includinga marked elevation in the serum of rifabutin at the expense ofsuppressing the clarithromycin, whose serum concentrations found laterin pharmacokinetic studies, came close to suboptimal even at therecommended oral drug doses, threatening resistance development (Hafner,R., et al., Antimicrobial Agents and Chemotherapy, March 1998, Vol. 42,No. 3, pages 631-639), Conversely, this produced a situation where somepatients had blood drug levels which were bordering on adverse effectranges, e.g., possibly close to causing leucopenia or uveitis. Inaddition, clofazimine levels with separate drugs were slow to reachequilibrium.

Considering the above described unwanted interactions and the undesiredresults of Borody, an improved formulation was desired to address theseshortcomings.

SUMMARY

In one aspect, the present disclosure provides a pharmaceuticalcomposition comprising rifabutin, clarithromycin, clofazimine, and apharmaceutically acceptable carrier, wherein the amount of clofazimineis 10-15% w/w relative to the amount of clarithromycin and 20-25% w/wrelative to the amount of rifabutin.

In one embodiment, the present disclosure provides a method ofincreasing the reduced metabolism of rifabutin caused by clarithromycinin a patient, comprising co-administering clofazimine with rifabutin andclarithromycin to the patient, wherein the amount of clofazimine is6-18% w/w relative to the amount of clarithromycin.

Also provided is a method of reducing the increased metabolism ofclarithromycin caused by rifabutin in a patient, comprisingco-administering clofazimine with rifabutin and clarithromycin to thepatient, wherein the amount of clofazimine is 6-18% w/w relative to theamount of clarithromycin.

The present disclosure, in some embodiments, provides a method oftreating a patient suffering from or susceptible to a Mycobacteriumparatuberculosis infection, comprising co-administering to the patientin a single dosage form rifabutin, clarithromycin, and clofazimine in a9±0.0.5:19±0.5:2±0.5 w/w/w ratio.

Also contemplated is a method of inhibiting occurrence of aMycobacterium paratuberculosis infection in a patient, comprisingsimultaneously co-administering to the patient in need thereof (i) 225mg±2 mg rifabutin, (ii) 475 mg±2 mg clarithromycin, and (iii) 50 mg±1 mgclofazimine once each day.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures depict illustrative aspects of presentcompositions and methods and not intended to be limiting in any way.

FIGS. 1a-b depict mean clarithromycin plasma concentration-time profilesin linear and semi-logarithmic plots, respectively.

FIGS. 2a-b depict mean 14-hydroxyclarithromycin plasmaconcentration-time profiles in linear and semi-logarithmic plots,respectively.

FIGS. 3a-b depict mean rifabutin plasma concentration-time profiles inlinear and semi-logarithmic plots, respectively.

FIGS. 4a-b depict mean 25-O-desacetylrifabutin plasma concentration-timeprofiles in linear and semi-logarithmic plots, respectively.

FIGS. 5a-b depict mean clofazimine plasma concentration-time profiles inlinear and semi-logarithmic plots, respectively.

DETAILED DESCRIPTION 1. Compositions

The present description provides compositions comprising rifabutin,clarithromycin, and clofazimine and methods of using same. Therifabutin, clarithromycin, and clofazimine of the compositions areprovided in ratios that yield improved pharmacokinetic properties. Thepresent compositions reduce potentially deleterious elevations ofrifabutin serum concentration that resulted from administration ofearlier known formulations. In contrast to earlier known formulations,the present compositions further provide the advantage of maintainingpatient blood drug levels well below adverse effect ranges, e.g., belowranges implicating leucopenia or uveitis. Moreover, the subjectcompositions also maintain higher levels of serum concentrations ofclarithromycin as compared to earlier formulations, thereby inhibitingresistance development. Furthermore, the present compositions allowreaching minimum effective patient clofazimine serum levels faster thanwith previous formulations.

In one embodiment, present compositions comprise rifabutin,clarithromycin, clofazimine, and a pharmaceutically acceptable carrier,wherein the amount of clofazimine is 5-18% w/w relative to the amount ofclarithromycin (such as, 7-16%, 9-14%, 9-12%, 10-15%, or 0-11% w/w) and10-25% w/w relative to the amount of rifabutin (such as, 12-25%, 12-23%,15-25%, 15-23%, 18-25%, 18-23%, 20-25%, 20-23%, or 21-23%).

In further embodiments, the present compositions comprise rifabutin,clarithromycin, and clofazimine in about a 9:19:2 w/w/w ratio, whereineach of the variables are free to vary ±2, 1, 0.5, or 0.25 (e.g.,9±0.5:19±5:2±0.5). For example in some instances, the presentcompositions comprise 90 mg rifabutin (±30, 20, 10, 5, 2, or 1 mg), 190mg clarithromycin (±60, 40, 20, 10, 5, 2, or 1 mg), and 20 mgclofazimine (±10, 7, 5, 2, or 1 mg). In another instance, the presentcompositions comprise 45 mg rifabutin (±15, 10, 7, 5, 2, or 1 mg), 95 mgclarithromycin (±30, 20, 10, 5, 2, or 1 mg), and 10 mg clofazimine (±6,5, 2, or 1 mg).

In some instances the present compositions further comprise anabsorption enhancer that may improve bioavailability of one or more ofthe active ingredients. The amount of absorption enhancer may between300-700% w/w relative to the amount of clofazimine including 400-600% or450-550% or 475-525%. In certain embodiments, the absorption enhancer ispolyethylene glycol (PEG), for example, polyethylene glycol having anaverage molecular weight of between 200-20,000 including between1000-15000 or 5000-12000 or 7000-9000 or 7500-8500, for example PEG8000).

The present compositions may further include one or more additionalexcipients, such as Microcrystalline cellulose (MCC)TABULOSE® SC 200),Mg Stearate, Sodium Lauryl Sulfate (SLS) EMAL® 10Pwd HD, a polysorbate(such as, polysorbate 80), or a combination thereof, including all ofthese. In some instances, the present compositions include bothpolyethylene glycol and a polysorbate, such as polysorbate 80, whereinthe amount of polysorbate is 30-120% w/w relative to the amount ofclofazimine (such as 50-100%, 50-85%, or 60-75%). Additional excipientscontemplated for use with the present compositions are described furtherbelow.

The present compositions may further include one or more ionic ornon-ionic surfactants. In particular, the present compositions maycomprise sodium lauryl sulfate.

In one embodiment, the present compositions are provided in a singledosage form, for example a tablet, capsule, caplet or lozenge, etc.Additional contemplated dosage forms are described further below.

2. Methods of Treatment

The present compositions are useful for treating a patient sufferingfrom or susceptible to a Mycobacterium paratuberculosis (MAP) infection.In some instances, such treatments include the treatment of inflammatorybowel disease (IBD), such as Crohn's disease, ulcerative colitis,indeterminate colitis, microscopic colitis and collagenous colitis, inaddition to sarcoidosis. In preferred embodiments, the present methodsare useful for the treatment of Crohn's disease or colitis.

Hence, in one embodiment the present methods include a method oftreating a patient suffering from or susceptible to a Mycobacteriumparatuberculosis infection, comprising co-administering to the patientin a single dosage form rifabutin, clarithromycin, and clofazimine in a8-10:18-20:1-2.5 w/w/w ratio (for example, a 8.5-9.5:18.5-19.5:1.5-2.5w/w/w ratio or a 9:19:2 ratio, wherein each variable is free to vary±0.5 or 0.25). In another embodiment, the present method may include acomposition comprising a single dosage form comprising 90 mg rifabutin(±30, 20, 10, 5, 2, or 1 mg), 190 mg clarithromycin (±60, 40, 20, 10, 5,2, or 1 mg), and 20 mg clofazimine (±10, 7, 5, 2, or 1 mg). In anotherembodiment, the present method may include a composition comprising 45mg rifabutin (±15, 10, 7, 5, 2, or 1 mg), 95 mg clarithromycin (±30, 20,10, 5, 2, or 1 mg), and 10 mg clofazimine (±6, 5, 2, or 1 mg).

In some instances, the rifabutin, clarithromycin, and clofazimine areco-administered once each day for a first period of treatment (forexample, 1-3 weeks, including 1 week, 2 weeks or three weeks) in thefollowing amounts: (i) 80-100 mg rifabutin (such as, 85-95 mg or 90mg±1.5 mg), (ii) 180-200 mg clarithromycin (such as, 185-195 mg or 190mg±2 mg), and (iii) 15-25 mg clofazimine (such as 17-23 mg or 20±1 mg).The method may further include the step of linearly increasing theamounts of the rifabutin, clarithromycin, and clofazimine whilemaintaining a 8-10:18-20:1-2.5 w/w/w ratio (for example, a8.5-9.5:18.5-19.5:1.5-2.5 w/w/w ratio or a 9:19:2 ratio, wherein eachvariable is free to vary ±0.5 or 0.25 ratio) for a second period oftreatment (for example, from 4-10 weeks). In an embodiment, the linearlyincreasing amounts of the rifabutin, clarithromycin, and clofazimine donot exceed maximum amounts of (i) 420-480 mg rifabutin (such as, 440-460mg or 450 mg), 920-980 mg clarithromycin (such as, 940-960 mg or 950mg), and (iii) 80-120 mg clofazimine (such as, 90-110 mg or 100 mg)during the second period of treatment. In certain instances, thelinearly increasing amounts of rifabutin, clarithromycin, andclofazimine comprise:

a) (i) 160-200 mg rifabutin (such as, 170-190 mg or 180 mg±2 mg), (ii)360-400 mg clarithromycin (such as, 370-390 mg or 380 mg±2 mg), and(iii) 30-50 mg clofazimine (such as, 35-45 mg or 40 mg±1 mg) once eachday for two weeks;

b) (i) 250-290 mg rifabutin (such as, 260-280 mg or 270 mg±2 mg), (ii)550-590 mg clarithromycin (such as, 560-580 mg or 570±2 mg), and (iii)50-70 mg clofazimine (such as, 55-65 mg or 60 mg±1.5 mg) once each dayfor two weeks;

c) (i) 340-380 mg rifabutin (such as, 350-370 mg or 360 mg±2 mg), (ii)740-780 mg clarithromycin (such as 750-770 mg or 760 mg±2 mg), and (iii)60-100 mg clofazimine (such as, 70-90 mg or 80 mg±1.5 mg) once each dayfor two weeks; and

d) (i) 420-480 mg rifabutin (such as, 440-460 mg or 450 mg±2 mg), (ii)920-980 mg clarithromycin (such as, 940-960 mg or 950 mg±2 mg), and(iii) 80-120 mg clofazimine (such as, 90-110 mg or 100 mg±1.5 mg) onceeach day for a week.

In certain embodiments, the method further includes, following step d)above, the step of simultaneously co-administering (i) 420-480 mgrifabutin (such as, 440-460 mg or 450 mg±2 mg), (ii) 920-980 mgclarithromycin (such as, 940-960 mg or 950 mg±2 mg), and (iii) 80-120 mgclofazimine (such as, 90-110 mg or 100 mg±1.5 mg) once each day for athird period of treatment. In some embodiments, the third period oftreatment is 1, 2, 4, 6, 8, 12 weeks; 3, 6, or 12 months or longer. Inone embodiment the third period of treatment continues until the MAPinfection has been treated, for example, to the point of eradication,reduction, or at least to the point of halting the progression of theinfection.

In some instances, the method further includes, after the MAP infectionhas been treated, the step of simultaneously co-administering to thepatient (i) 210-240 mg rifabutin (such as, 220-230 mg or 225 mg±2 mg),(ii) 460-490 mg clarithromycin (such as, 470-480 mg or 475 mg±2 mg), and(iii) 40-60 mg clofazimine (such as, 45-55 mg or 50 mg±1 mg) once eachday, for example, to inhibit recurrence or prevent recurrence of MAPinfection. In some instances, the patient was previously treated with acombination of rifabutin, clarithromycin, and clofazimine. Alsocontemplated is a method of inhibiting occurrence of a Mycobacteriumparatuberculosis infection in a patient, comprising simultaneouslyco-administering to the patient in need thereof (i) 210-240 mg rifabutin(such as, 220-230 mg or 225 mg±2 mg), (ii) 460-490 mg clarithromycin(such as, 470-480 mg or 475 mg±2 mg), and (iii) 40-60 mg clofazimine(such as, 45-55 mg or 50 mg±1 mg) once each day.

The present methods further contemplate a method of increasing thereduced metabolism of rifabutin caused by clarithromycin in a patient;comprising co-administering clofazimine with rifabutin andclarithromycin to the patient, wherein the amount of clofazimine is5-18% w/w relative to the amount of clarithromycin, for example, 6-18%,7-16%, 9-14%, 9-12%, 10-15%, or 10-11% w/w.

In another embodiment, the present methods further include a method ofreducing the increased metabolism of clarithromycin caused by rifabutinin a patient, comprising co-administering clofazimine with rifabutin andclarithromycin to the patient, wherein the amount of clofazimine is5-18% w/w relative to the amount of clarithromycin, for example, 6-18%,7-16%, 9-14%, 9-12%, 10-15%, or 10-11% w/w.

The present methods further contemplate a method of increasing thereduced metabolism of rifabutin caused by clarithromycin in a patient,comprising co-administering clofazimine with rifabutin andclarithromycin to the patient, wherein the amount of clofazimine is10-25% w/w relative to the amount of rifabutin, for example, 12-25%,12-23%, 15-25%, 15-23%, 18-25%, 18-23%, 20-25%, 20-23%, or 21-23% w/w.

In another embodiment, the present methods further include a method ofreducing the increased metabolism of clarithromycin caused by rifabutinin a patient, comprising co-administering clofazimine with rifabutin andclarithromycin to the patient, wherein the amount of clofazimine is10-25% w/w relative to the amount of rifabutin, for example, 12-25%,12-23%, 15-25%, 15-23%, 18-25%, 18-23%, 20-25%, 20-23%, or 21-23% w/w.

In certain instances, the increase in rifabutin metabolism in the abovemethods is assessed by measuring a first C_(max) of rifabutin or25-O-desacetyl rifabutin in the patient's serum following administrationof clofazimine and comparing the first C_(max) to a second C_(max) ofrifabutin or 25-O-desacetyl rifabutin. The second C_(max), of rifabutinor 25-O-desacetyl rifabutin may correspond to a reference value, forexample, an average or mean value obtained from the literature, from oneor more other patients with similar physical profiles (age, health,metabolism, and/or disease profile, etc.) or from the same patient at anearlier time. For instance, in some embodiments, the second C_(max) ofrifabutin or 25-O-desacetyl rifabutin is measured in a second patient'sserum, wherein the second patient has been co-administered rifabutin andclarithromycin without co-administration of clofazimine. In anotherembodiment, the second C_(max) of rifabutin or 25-O-desacetyl rifabutinwas previously measured in the same patient's serum, wherein the samepatient had been co-administered rifabutin and clarithromycin withoutco-administration of clofazimine.

In one embodiment, the first C_(max) of rifabutin is decreased ascompared to the second C_(max) of rifabutin by at least 5%, 10%, 20%,30, or 40%. In another embodiment, the first C_(max) of 25-O-desacetylrifabutin is decreased as compared to the second C_(max) of25-O-desacetyl rifabutin by at least 5%, 10%, 20%, 30, or 40%.

In some instances, the increase in rifabutin metabolism in the abovemethods is assessed by measuring a first AUC₀₋₂₄ of 25-O-desacetylrifabutin in the patient's serum following co-administration ofclofazimine and comparing the first AUC to a second AUC₀₋₂₄ of25-O-desacetyl rifabutin. The second AUC₀₋₂₄ of 25-O-desacetyl rifabutinmay correspond to a reference value, for example, an average or meanvalue obtained from the literature, from one or more other patients withsimilar physical profiles (age, health, metabolism, and/or diseaseprofile, etc.) or from the same patient at an earlier time. For example,in certain instances, the second AUC₀₋₂₄ of 25-O-desacetyl rifabutin ismeasured in a second patient's serum, wherein the second patient hasbeen co-administered rifabutin and clarithromycin withoutco-administration of clofazimine. In another embodiment, the secondAUC₀₋₂₄ of 25-O-desacetyl rifabutin was previously measured in the samepatient's serum, wherein the same patient had been co-administeredrifabutin and clarithromycin without co-administration of clofazimine.

In one embodiment, the first AUC₀₋₂₄ is decreased as compared to thesecond AUC₀₋₂₄ by at least 5%, 10%, 20%, 30, or 40%.

For the compositions employed in the present methods, in some instances,at least two of the rifabutin, the clarithromycin, and the clofaziminearc co-formulated into a single dosage form. For example, in someinstances, each of the rifabutin, the clarithromycin, and theclofazimine are co-formulated into a single dosage form.

Any of the above-mentioned compositions are contemplated for use withthe present methods. For example, in some instances the present methodscontemplate use of compositions comprising an absorption enhancer thatmay improve bioavailability of one or more of the active ingredients.The amount of absorption enhancer may between 300-700% w/w relative tothe amount of clofazimine (such as, 400-600%, 450-550%, or 475-525%). Incertain embodiments, the absorption enhancer is polyethylene glycol, forexample, polyethylene glycol having an average molecular weight ofbetween 200-20,000 (such as, between 1000-15000, 5000-12000, 7000-9000,or 7500-8500, for example PEG 8000).

3. Methods Including Immunization with Mycobacterial Extract or Product

The present methods further contemplate a method for the treatment ofinflammatory bowel disease comprising administering to a patient in needof such treatment effective amounts of rifabutin, clarithromycin, andclofazimine, in ratios, dosages, and/or dosage forms as describedherein, and immunizing the patient with an immunizing amount of amycobacterial extract or product. For example, a patient previously nottreated or on current anti-inflammatory therapies may be treated byimmunization with a mycobacterial extract or product (living or dead, orits extracted wall and DNA components) as an immunizing agent tostimulate leucocytes in the immunized patient. Such immunizing agentsmay be extracts or products from known, non-pathogenic mycobacteria suchas M. vaccae of M. phlei. As used herein, the expression “mycobacterialextract or product” refers to whole-killed mycobacteria or mycobacterialextract, with or without adjuvants. An example of a suitablemycobacterial product or extract is Regressin, available from Bionicheof London, Ontario, Canada.

The mycobacterial product may be used to recurrently immunize thepatient using the product as an immunostimulant. The mycobacterialproduct can be administered via any of several routes, such as oral,intravenous, intramuscular, or subcutaneous. Such immunizations canreduce or even rid the patient of the MAP infection and have the abilityto inhibit or cure the disease or place the patient into a prolongedremission.

Administration of the mycobacterial product or extract is typically fromweekly to monthly, but may be more or less frequent. An appropriatetreatment regime may be arrived at readily by a medical practitioner inany particular case, given the teaching herein. The mycobacterialproduct or extract may be administered before, after, or simultaneous toadministration of rifabutin, clarithromycin, and clofazimine.

Doses of the mycobacterial extract can be given in any frequency rangingfrom 25-500 μg, for example, 50-500 μg. In certain embodiments; adequateimmuno-stimulation can be maintained by weekly to monthly, typicallyweekly or monthly, regimens.

In another embodiment, therapy with Mycobacterium phlei extract (e.g.,Regressin) includes a weekly immunization program, increasing the dosageby 20-80 μg, for example, 40-60 μg or 50 μg, of the extract every weekuntil the patient develops fever, rigors, and nausea.

The dose is then dropped by 20-80 μg, for example, 40-60 μg or 50 μg, tothe lower level and the patient continues maintenance immunization on amonthly basis. The treatment can last from 4-8 weeks, such as 6 weeks,up to a monthly immunization program of 1-2 years or more.

In another form of therapy standard anti-inflammatory therapy can becombined with recurrent Regressin immunization.

Dosages of rifabutin, clarithromycin, and clofazimine used inconjunction with mycobacterial extract correspond to those describedabove. All combinations of the dosages and treatment schedules forrifabutin, clarithromycin, and clofazimine and mycobacterial extractdescribed herein are contemplated.

4. Additional Agents

The present methods further contemplate combined use with one or moreadditional agents, such as anti-TB agents, such as salazopyrin,olsalazine or mesalazine, as well as other less known aminosalicylicacids. The 4-aminosalicylic acids or 5-aminosalicylic acids can becombined with rifabutin, clarithromycin, and clofazimine. Dosages ofthese additional agents are generally known. For example the typicaldosage range for salazopyrin is in the range of from 500 mg to 4 g perday, and for olsalazine or mesalazine from 0.500 mg to 3 g per day.

Hence, the present methods may further include one or more agentseffective against tuberculosis.

Such additional agents may be administered before, after, orsimultaneous to administration of rifabutin, clarithromycin, andclofazimine. Furthermore, such agents may be administered as part of thesame dosage form (e.g., tablet, capsule, caplet, etc.) or in a differentdosage form as that including the rifabutin, clarithromycin, andclofazimine.

5. Dosage Forms

The present compositions may be available in the form of a tabletcontaining at least one of rifabutin, clarithromycin, and clofazimine ina powdered form. In some instances two or all of rifabutin,clarithromycin, and clofazimine are in a powdered form. Alternatively,present compositions may be in the form of a tablet capsule containingat least one of rifabutin, clarithromycin, and clofazimine in amicroencapsulated form. In some instances, two or all of rifabutin,clarithromycin, and clofazimine are in a microencapsulated form. Asanother possibility, present compositions may be in the form of a tabletcapsule containing at least one of rifabutin, clarithromycin, andclofazimine in a powdered form, and the remaining agents present in amicroencapsulated form. As a further possibility, present compositionsmay be in the form of a tablet capsule containing one or more ofrifabutin, clarithromycin, and clofazimine present in a microgranulatedform. In additional possibilities, present compositions may be in theform of a tablet containing one or more of rifabutin, clarithromycin,and clofazimine within a capsule, a capsule containing one or more ofrifabutin, clarithromycin, and clofazimine within a tablet, a capsulecontaining one or more of rifabutin, clarithromycin, and clofaziminewithin an outer capsule containing the other agents, or any combinationof the above.

In a further embodiment, the present compositions comprise an innercapsule containing rifabutin, within an outer capsule containingclarithromycin and clofazimine, wherein clarithromycin and clofaziminemay be present in powdered, microencapsulated, or microgranulated forms.

The present methods may be carried out by administration of one or moretablets/capsules containing rifabutin, clarithromycin, and clofazimineas described above, or through the administration of each of theseseparately. In preferred embodiments, rifabutin, clarithromycin, andclofazimine are administered simultaneously in one dose.

The present compositions may be prepared by means known in the art forthe preparation of pharmaceutical compositions including blending,grinding, homogenizing, suspending, dissolving, emulsifying, dispersing,and, where appropriate, mixing of rifabutin, clarithromycin, andclofazimine together with selected excipients, diluents, carriers andadjuvants.

For oral administration, the present compositions may be in the form oftablets, lozenges, pills, troches, capsules, elixirs, powders, includinglyophilized powders, solutions, granules, suspensions, emulsions, syrupsand tinctures. Slow-release, or delayed-release, forms may also beprepared, for example in the form of coated particles, multi-layertablets or microgranules.

Solid forms for oral administration may contain pharmaceuticallyacceptable binders, sweeteners, disintegrating agents, diluents,flavorings, coating agents, preservatives, lubricants, and/or time delayagents. Suitable binders include gum acacia, gelatin, corn starch, gumtragacanth, sodium alginate, carboxymethylcellulose or polyethyleneglycol (PEG). Suitable sweeteners include sucrose, lactose, glucose,aspartame or saccharine. Suitable disintegrating agents include cornstarch, methylcellulose, polyvinylpyrrolidone, xanthan gum, bentonite,alginic acid or agar. Suitable diluents include lactose, sorbitol,mannitol, dextrose, kaolin, cellulose, calcium carbonate, calciumsilicate or dicalcium phosphate. Suitable flavoring agents includepeppermint oil, oil of wintergreen, cherry, orange, or raspberryflavoring. Suitable coating agents include polymers or copolymers ofacrylic acid and/or methacrylic acid and/or their esters, waxes, fattyalcohols, zein, shellac or gluten. Suitable preservatives include sodiumbenzoate, vitamin E, alpha-tocopherol, ascorbic acid, methyl paraben,propyl paraben or sodium bisulphite. Suitable lubricants includemagnesium stearate, stearic acid, sodium oleate, sodium chloride ortalc. Suitable time delay agents include glyceryl monostearate orglyceryl distearate.

Liquid forms for oral administration may contain, in addition to theabove agents, a liquid carrier. Suitable liquid carriers include water,oils, such as olive oil, peanut oil, sesame oil, sunflower oil,safflower oil, arachis oil, coconut oil, liquid paraffin, ethyleneglycol, propylene glycol, polyethylene glycol, ethanol, propanol,isopropanol, glycerol, fatty alcohols, triglycerides, or mixturesthereof.

Suspensions for oral administration may further include dispersingagents and/or suspending agents. Suitable suspending agents includesodium carboxymethylcellulose, methylcellulose,hydroxypropylmethyl-cellulose, poly-vinyl-pyrrolidone, sodium alginateor ceryl alcohol. Suitable dispersing agents include lecithin,polyoxyethylene esters of fatty acids such as stearic acid,polyoxyethylene sorbitol mono- or di-oleate, -stearate or laurate,polyoxyethylene sorbitan mono- or -dioleate, -stearate or -laurate, andthe like.

Emulsions for oral administration may further include one or moreemulsifying agents. Suitable emulsifying agents include dispersingagents as exemplified above or natural gums such as gum acacia or gumtragacanth.

Variations, modifications, and other implementations of what isdescribed herein will occur to those of ordinary skill without departingfrom the spirit and the scope of the present disclosure. Accordingly,these are not to be limited only to the preceding illustrativedescription.

For additional illustrative features that may be used with the presentcompositions and methods, including the embodiments described here,refer to the documents listed herein, which are incorporated byreference in their entirety. All operative combinations between theabove described illustrative embodiments and those features described indocuments and references cited herein are considered to be potentiallypatentable embodiments.

EXEMPLIFICATION

With aspects of the present compositions and methods now being generallydescribed, these will be more readily understood by reference to thefollowing examples, which are included merely for purposes ofillustration of certain features and embodiments of the presentcompositions and methods invention and are not intended to be limiting.

1. Bioavailability Study

The objectives of this study were to 1) determine and compare the rateand extent of absorption and 2) to assess the safety and tolerability of2 test formulations of a combination product of clarithromycin,rifabutin and clofazimine (herein after “triple combination”).

This study followed a randomized, open-label, single-dose, 1-way 2-armparallel design in 24 normal, healthy, non-smoking male and femalesubjects. All subjects completed the study, and their data were used forpharmacokinetic and statistical analyses.

Subjects were admitted to the clinic the day before dosing, and remaineduntil the 24.00 hour post-dose blood draw, at which time they wereallowed to leave the clinic and after which they were required to returnfor subsequent blood draws. Following a high fat meal, subjects received2 triple combination capsules (dry formulation) or 2 triple combinationcapsules (PEG formulation) on Day 1 of the study period.

During the study, 19 blood samples were collected from each subject, forpharmacokinetic and statistical analyses. Over the course of the entirestudy, approximately 236.5 mL of blood was collected from male subjectsand approximately 241.5 mL of blood was collected from female subjects.These volumes include all required samples, as described further below.

The randomization scheme was computer-generated and subjects wereassigned a 15 treatment sequence before Period I dosing.

This was an open-label study; however, the bioanalytical group wasblinded to the randomization scheme. This scheme was made available forstatistical and reporting purposes only after the completion of thebioanalytical portion of the study.

Water was provided ad libitum until 1.0 hour pre-dose and after 1.0 hourpost-dose. With the exception of the whole milk provided to all subjectsduring the high fat content meal, the only fluid intake allowed duringthis time was 240 mL of ambient temperature dosing water.

Following an overnight fast of at least 10 hours, subjects began a highfat content meal 30 minutes prior to drug administration. Subjectsconsumed this meal in 30 minutes or less; however, the study drug wasadministered 30 minutes after the start of the meal. The FDA standardhigh-fat content breakfast consisted of the following: 2 eggs fried inbutter, 2 strips of bacon, 2 slices of toast with butter, 4 ounces ofhash brown potatoes and 8 fluid ounces (.about.240 mL) of whole milk.

No food was allowed for at least 4 hours post-dose. At 4.5, 9.5, and13.5 hours post-dose, standardized meals and beverages were provided tothe subjects. All meals and beverages were free of alcohol, grapefruitproducts, xanthines and caffeine and were identical for both studytreatments.

Treatments Administered

Following an overnight fast of at least 10 hours, and 30 minutes afterthe start of a high fat content meal, subjects received one of thefollowing treatments at 0.00 hour on Day 1 of the study period accordingto a randomization scheme:

Treatment A: 2 triple combination capsules (dry formulation) with 240 mLof ambient temperature water (Treatment Dose=190 mg of clarithromycin,90 mg of rifabutin and 20 mg of clofazimine).

Treatment B: 2 triple combination capsules (PEG formulation) with 240 mLof ambient temperature water (Treatment Dose=190 mg of clarithromycin,90 mg of rifabutin and 20 mg of clofazimine).

The medications were administered orally. The drugs were given 1 or morecapsules at a time. All capsules were ingested within 1 minute.

Blood Processing

Approximately 236.5 mL, of blood was collected from male subjects and241.5 mL of blood was collected from female subjects over the studyperiod, as detailed in:

TABLE 1 Volume Taken per Subject Male Female Procedure Subjects SubjectsPre-Study 19.5 mL 19.5 mL Serum p-CG Tests N/AP   5 mL Interim Lab Tests13.5 mL 13.5 mL (Biochemistry and Haematology) PK Blood Samples  190 mL 190 mL End-of-Study Examination 13.5 mL 13.5 mL Total Blood Volume236.5 mL  241.5 mL 

During the study period, 19 blood samples (1.times.4 mL and 1.times.6 mLtube for each sampling time point) were collected from each subject bydirect venipuncture or by Vasofix® intravenous catheter usingpre-cooled, labelled blood collection tubes containing potassiumethylenediaminetetraacetic acid (EDTA) as the anticoagulant. Bloodsamples were collected at 0.00 (pre-dose), 0.25, 0.50, 0.75, 1.00, 1.50,2.00, 2.50, 3.00, 4.00, 6.00, 8.00, 10.00, 12.00, 16.00, 24.00, 48.00,60.00, and 96.00 hours post-dose. The clock times of all blood draws forplasma concentration analyses were recorded.

The 6 mL tubes were used to measure clarithromycin and14-hydroxyclarithromycin. The 4 mL tubes were used to measure rifabutin,25-O-desacetylrifabutin and clofazimine.

The blood samples were stored in an ice bath before centrifugation andwere centrifuged as soon as possible under refrigerated conditions (at4° C.) at 3500 rpm for 7 minutes. The collected plasma from each bloodcollection tube was aliquotted into pre-cooled labelled polypropylenetubes. A minimum of 1.5 mL of plasma was transferred from the 6 mL tubesinto the first polypropylene tube, and all remaining plasma, if any, wastransferred into a second polypropylene tube. The samples were kept inan ice bath, and flash frozen in an upright position, then stored at−70±10° C. until assayed.

In another procedure, the blood samples were stored in an ice bathbefore centrifugation and were centrifuged as soon as possible underrefrigerated conditions (at 4° C.) at 3500 rpm for 7 minutes. Thecollected plasma from each blood collection tube was aliquotted intopre-cooled labelled polypropylene tubes. A minimum of 0.8 mL of plasmawas transferred from the 4 mL, tubes into the first polypropylene tube,and all remaining plasma, if any, was transferred into a secondpolypropylene tube. The samples were kept in an ice bath, and flashfrozen in an upright position, then stored at −70±10° C. until assayed.

Upon completion of the clinical portion of the study, all samples wereanalysed for clarithromycin and 14-hydroxyclarithromycin in the plasmasamples or for rifabutin, 25-O-desacetylrifabutin and clofazimine in theplasma samples.

Measurements

The direct measurements of this study were the plasma concentrations ofclarithromycin and 4-hydroxyclarithromycin performed, and rifabutin,25-O-desacetylrifabutin, and clofazimine performed.

The pharmacokinetic parameters were derived from the plasmaclarithromycin, 14-hydroxyclarithromycin, rifabutin,25-O-desacetylrifabutin, and clofazimine concentrations.

Bioanalyses

Clarithromycin and 14-hydroxyclarithromycin—Information about theseanalytes was obtained using routine methods known in the art.

Rifabutin, 25-O-Desacetylrifabutin, and Clofazimine—Rifabutin,25-O-desacetylrifabutin, clofazimine, and the internal standard,diltiazem, were extracted by solid phase extraction into an organicmedium from 0.20 mL of human plasma. An aliquot of this extract wasinjected into a High Performance Liquid Chromatography system anddetected using a mass spectrometer. The analytes were separated byreverse phase chromatography. Evaluation of the assay was carried out bythe construction of an eight (8) point calibration curve (excluding zeroconcentration) covering the range of 9.996 ng/mL to 1279.470 ng/mL forrifabutin, 2.499 ng/mL to 319.917 ng/mL for 25-O-desacetylrifabutin, and4.997 ng/mL to 639.586 ng/L., for clofazimine in human plasma.

The slope and intercept of the calibration curves were determinedthrough weighted linear regression analysis (I/conc.²). Two calibrationcurves and duplicate QC samples (at 3 concentration levels) wereanalysed along with each batch of the study samples. Peak area ratioswere used to determine the concentration of the standards, qualitycontrol samples, and the unknown study samples from the calibrationcurves.

Pharmacokinetic Analysis

The following pharmacokinetic parameters for clarithromycin, rifabutinand clofazimine and the metabolites 14-hydroxyclarithromycin and25-O-desacetylrifabutin were calculated by standard non-compartmentalmethods: AUC_(0-t), AUC_(0-inf), AUC_(0-t)/AUC_(0-inf), C_(max),T_(max), t_(1/2), K_(el), and M/P ratio.

Using General Linear Model (GLM) procedures in Statistical AnalysisSystem (SAS), analysis of variance (ANOVA) was performed onIn-transformed AUC_(0-t), AUC_(0-inf), AUC_(0-t)/AUC_(0-inf), andC_(max) and on untransformed t_(1/2) K_(el), and M/P ratio at thesignificance level of 0.05. The intra-subject coefficient of variation(CV) was calculated using the Mean Square Error (MSE) from the ANOVAtable. The ratio of geometric means and the 90% geometric confidenceinterval (90% C.I.) were calculated based on the difference in the LeastSquares Means of the In-transformed AUC_(0-t), AUC_(0-inf),AUC_(0-t)/AUC_(0-inf), and C_(max) between the dry and PEG formulations.T_(max) was analysed using nonparametric methods.

The pharmacokinetic parameters for clarithromycin,14-hydroxyclarithromycin, rifabutin, 25-O-desacetylrifabutin, andclofazimine derived for both treatments were:

Primary Parameters:

AUC_(0-t)=area under the concentration-time curve from time zero to timeof last measurable concentration, calculated using the lineartrapezoidal rule

AUC_(0-inf)=area under the concentration-time curve from time zero toinfinity

C_(max)=maximum plasma concentration after dosing

Secondary Parameters:

AUC_(0-t)/AUC_(0-inf)=Ratio of AUC_(0-t) to AUC_(0-inf)

T_(max)=time to reach peak plasma concentration

K_(el)=first order terminal elimination rate constant

t_(1/2)=terminal half-life

M/P ratio=Metabolite/Parent ratio for AUC_(0-inf)-(the conversion tomolar units occurs prior to the computation of the ratio).

The arithmetic mean, standard deviation (SD) and CV were calculated forplasma clarithromycin, 14-hydroxyclarithromycin, rifabutin,25-O-desacetylrifabutin, and clofazimine concentrations for eachsampling time and formulation, and for the PK parameters AUC_(0-t),AUC_(0-inf), AUC_(0-t)/AUC_(0-inf), C_(max), T_(max), t_(1/2), K_(el),and M/P ratio.

ANOVAs (with the following factors: treatment, period, sequence, subjectwithin sequence) were performed on the In-transformed data forAUC_(0-t), AUC_(0-inf), AUC_(0-t)/AUC_(0-inf), C_(max). ANOVAs were alsoperformed on the untransformed data to compare the t_(1/2), K_(el), andM/P ratio. All ANOVAs were performed with the SAS GLM Procedure. T_(max)was analysed using nonparametric methods. The equality of treatmenteffect in both arms was evaluated using Wilcoxon rank-sum tests. For allanalyses, effects were considered statistically significant if thep-value associated with was less than or equal to 0.050.

Based on the ANOVA results and the pair-wise comparisons of theIn-transformed AUC_(0-t), AUC_(0-inf), AUC_(0-t)/AUC_(0-inf), C_(max)data, the intra-subject CV, the relative ratios of the geometric means(calculated according to the formula: e^([dry-PEG])×100%), and the 90%geometric C.I. were determined.

Twenty-four subjects participated in this study, and samples from the 24completing subjects (12 per arm) were assayed for drug concentration.

The principal statistical software used was SAS®, version 8.2. Allanalyses were performed on the platform of the SAS® suite of statisticalprograms, using coded procedures that have been written and verified bythe staff in the Pharmacokinetics and Statistics Department of BCR.

Twenty-four subjects (12 males and 12 females) with a mean age of 31years (range=18 to 45 years) were enrolled in and completed the study.The completing subjects' mean height was 170 cm (range=149 to 187 cm)and their mean weight was 71 kg (range=48 to 104 kg). The subjects' meanBMI was 24.7 kg/m² (range=18.6 to 29.7 kg/m₂). The completing subjectsconsisted of 9 Caucasians, 5 Asians, 5 Blacks and 4 Hispanics and 1Mulatto.

Bioanalytical Results

Clarithromycin and 14-Hydroxyclarithromycin—Information about theseanalytes was obtained using routine methods known in the art.

Rifabutin, 25-O-Desacetylrifabutin, and Clofazimine—The plasma sampleswere analysed for rifabutin, 25-O-desacetylrifabutin, and clofazimine.

Accuracy and precision of this method were evaluated both within run(intra-assay—Table 2) and between runs (inter-assay—Table 3) by theanalysis of the lowest limit of quantification (LLOQ) and QualityControl samples at 3 different concentrations (QC HIGH, QC MED and QCLOW) in human plasma prepared in the range of the calibration/standardcurve. The accuracy and precision determined, at each concentrationlevel, were reported as percent relative error (% RE) and percentcoefficient of variation (% CV), respectively.

TABLE 2 Intra-Batch Parent Metabolite Parent Analyte name rifabutin25-0- clofazimine desacetylrifabutin QC Intraday precision   4.2 to 8.7  5.3 to 10.0 2.3 to 7.7 range (%) QC Intraday accuracy −3.9 to 1.1 −7.5to 9.3 0.6 to 7.0 range (%)

TABLE 3 Inter-Batch Parent Metabolite Parent Analyte name rifabutin25-0- clofazimine desacetylrifabutin QC Intraday precision   5.1 to 7.6  4.9 to 10.4 5.1 to 7.2 range (%) QC Intraday accuracy −0.2 to 3.0 −1.4to 3.9 0.4 to 5.2 range (%)Long Term Stability in Matrix—Long term stability of rifabutin,25-O-desacetylrifabutin, and clofazimine in human plasma can bedetermined by comparing the concentration of freshly prepared (notfrozen) QC samples (QC LOW and QC HIGH) with aged QC samples of the sameconcentration.Pharmacokinetic Profiles

Mean clarithromycin, 14-hydroxyclarithromycin, rifabutin,25-O-desacetylrifabutin, and clofazimine plasma concentration-timeprofiles (linear and semi-logarithmic plots) are presented in FIGS. 1,2, 3, 4, and 5, respectively.

The mean pharmacokinetic parameters for clarithromycin,14-hydroxyclarithromycin, rifabutin, 25-O-desacetylrifabutin, andclofazimine are summarized below in Tables 4, 5, 6, 7, and 8,respectively.

TABLE 4 PHARMACOKINETIC PARAMETERS FOR CLARITHROMYCIN Geometric Mean (%CV) Arithmetic Mean ± SD Triple Triple Combination Capsules CombinationCapsules Pharmacokinetic (dry formulation) (PEG formulation) Parameters(A) (n = 12) (B) (n = 12) AUC_(0-t) (ng hr/mL) 2388.54 (66.38) 2972.86(54.97) 3123.93 ± 2073.75 3450.66 ± 1896.84 AUC_(0-inf) 2462.93 (65.56)3049.00 (54.50) (ng hr/mL) 3194.76 ± 2094.48 3520.31 ± 1918.52AUC_(0-t)/AUC_(0-inf) 96.98 (1.76) 97.50 (1.96) (%) 96.99 ± 1.70  97.52± 1.91  C_(max) (ng/mL) 364.30 (55.76) 485.54 (46.14) 450.69 ± 251.30549.18 ± 253.41 T_(max) (hr)* 4.00 (1.00-6.00) 4.00 (2.00-6.00) T_(1/2)(hr) 3.13 ± 0.72 3.17 ± 0.52 K_(el) (hr⁻¹) 2.35E−01 ± 6.74E−02 2.24E−01± 3.75E−02

TABLE 5 PHARMACOKINETIC PARAMETERS FOR 14-HYDROXYCLARITHROMYCINGeometric Mean (% CV) Arithmetic Mean ± SD Triple Triple CombinationCapsules Combination Capsules Pharmacokinetic (dry formulation) (PEGformulation) Parameters (A) (n = 12) (B) (n = 12) AUC_(0-t) (ng hr/mL)2671.07 (49.71) 2868.16 (34.51) 3015.37 ± 1499.06 3119.41 ± 1076.45AUC_(0-inf) 2704.76 (49.93) 2904.20 (33.94) (ng hr/mL) 3055.45 ± 1525.663145.08 ± 1067.45 AUC_(0-t)/AUC_(0-inf) 98.75 (1.05) 98.76 (1.61) (%)98.76 ± 1.03  98.77 ± 1.59  C_(max)(ng/mL) 261.17 (48.85) 296.82 (34.49)292.43 ± 142.86 324.26 ± 111.82 T_(max) (hr)* 4.00 (2.00-8.00) 4.00(2.50-6.00) T_(1/2) (hr) 7.52 ± 2.44 6.66 ± 1.82 K_(el) (hr⁻¹) 1.04E−01± 4.21E−02 1.12E−01 ± 3.14E−02 M/P Ratio (hr) 1.20 ± 0.63 0.99 ± 0.37

TABLE 6 PHARMACOKINETIC PARAMETERS FOR RIFABUTIN Geometric Mean (% CV)Arithmetic Mean ± SD Triple Triple Combination Capsules CombinationCapsules Pharmacokinetic (dry formulation) (PEG formulation) Parameters(A) (n = 12) (B) (n = 12) AUC_(0-t) (ng hr/mL) 1461.26 (57.71) 1897.71(36.42) 1633.40 ± 942.60 2023.01 ± 736.79 AUC_(0-inf) 1499.70 (31.80)2047.97 (39.63) (ng hr/mL)  1577.68 ± 501.76†  2200.58 ± 872.14‡AUC_(0-t)/AUC_(0-inf) 83.65 (6.71) 81.83 (8.94) (%) 83.84 ± 5.63 82.14 ±7.34 C_(max) (ng/mL) 142.75 (39.94) 160.87 (26.66) 151.41 ± 60.47 166.39 ± 44.37  T_(max) (hr)* 6.00 (2.50-6.12) 6.00 (4.00-8.00) T_(1/2)(hr) 10.80 ± 5.68† 14.43 ± 6.83‡ K_(el) (hr⁻¹)  8.44E−02 ± 4.77E−02† 6.07E−02 ± 3.30E−02‡

TABLE 7 PHARMACOKINETIC PARAMETERS FOR 25-0-DESACETYLRIFABUTIN GeometricMean (% CV) Arithmetic Mean ± SD Triple Triple Pharmaco- CombinationCapsules Combination Capsules kinetic (dry formulation) (PEGformulation) Parameters (A) (n = 12) (B) (n = 12) AUC_(0-t) 1461.26(57.71) 1897.71 (36.42) (ng hr/mL) 1633.40 ± 942.60 2023.01 ± 736.79AUC_(0-inf) 1499.70 (31.80) 2047.97 (39.63) (ng hr/mL)  1577.68 ±501.76†  2200.58 ± 872.14‡ AUC_(0-t)/ 83.65 (6.71) 81.83 (8.94)AUC_(0-inf) (%) 83.84 ± 5.63 82.14 ± 7.34 C_(max) (ng/mL) 142.75 (39.94)160.87 (26.66) 151.41 ± 60.47 166.39 ± 44.37 T_(max) (hr)* 6.00(2.50-6.12) 6.00 (4.00-8.00) T_(1/2) (hr)  10.80 ± 5.68†  14.43 ± 6.83‡K_(el) (hr⁻¹)  8.44E−02 ± 4.77E−02†  6.07E−02 ± 3.30E−02‡

TABLE 8 PHARMACOKINETIC PARAMETERS FOR CLOFAZIMINE Geometric Mean (% CV)Arithmetic Mean ± SD Triple Triple Combination Capsules CombinationCapsules Pharmacokinetic (dry formulation) (PEG formulation) Parameters(A) (n = 12) (B) (n = 12) AUC_(0-t) (ng hr/mL) 696.93 (57.71) 680.75(47.37) 829.07 ± 461.86 769.72 ± 364.62 AUC_(0-inf) 1242.28 (37.19)1030.78 (41.69) (ng hr/mL) 1304.12 ± 484.95† 1088.58 ± 453.78‡AUC_(0-t)/AUC_(0-inf) 76.08 (17.55) 64.28 (27.44) (%) 77.55 ± 13.6168.26 ± 18.73 C_(max) (ng/mL) 33.01 (54.75) 27.82 (38.14) 38.32 ± 20.9829.82 ± 11.37 T_(max) (hr)* 8.00 (2.50-24.00) 8.00 (4.00-12.00) T_(1/2)(hr) 23.25 ± 4.49† 21.28 ± 8.27‡ K_(el) (hr⁻¹)  3.07E−02 ± 5.75E−03† 3.55E−02 ± 1.14E−02‡

The relative bioavailability analysis results for AUC_(0-t),AUC_(0-inf), AUC_(0-t)/AUC_(0-inf), C_(max), and for clarithromycin,14-hydroxyclarithromycin, rifabutin, 25-O-desacetylrifabutin, andclofazimine are summarized above in Tables 9, 10, 11, 12, and 13,respectively.

TABLE 9 RELATIVE BIOAVAILABILITY ASSESSMENTS FOR CLARITHROMYCINParameter 90% C.I. Ratio of Means AUC_(0-t) 47.58% to 135.69% 80.34%AUC_(0-inf) 48.33% to 135.03% 80.78% C_(max) 46.57% to 120.88% 75.03%

TABLE 10 RELATIVE BIOAVAILABILITY ASSESSMENTS FOR14-HYDROXYCLARITHROMYCIN Parameter 90% C.I. Ratio of Means AUC_(0-t)65.11% to 133.20% 93.13% AUC_(0-inf) 65.43% to 132.57% 93.13% C_(max)61.72% to 125.43% 87.99%

TABLE 11 RELATIVE BIOAVAILABILITY ASSESSMENTS FOR RIFABUTIN Parameter90% C.I. Ratio of Means AUC_(0-t) 57.12% to 103.80% 77.00% AUC_(0-inf)53.02% to 101.13% 73.23% C_(max) 71.44% to 110.23% 88.74%

TABLE 12 RELATIVE BIOAVAILABILITY ASSESSMENTS FOR 25-0-DESACETYLRIFABUTIN Parameter 90% C.I. Ratio of Means AUC_(0-t) 48.10% to113.68% 73.95% AUC_(0-inf) 56.74% to 130.54% 86.06% C_(max) 55.19% to97.71%  73.43%

TABLE 13 RELATIVE BIOAVAILABILITY ASSESSMENTS FOR CLOFAZIMINE Parameter90% C.I. Ratio of Means AUC_(0-t) 66.12% to 158.52% 102.38% AUC_(0-inf)75.50% to 192.39% 120.52% C_(max) 83.26% to 169.02% 118.63%

Pharmacokinetic Conclusions

Based on data from 12 completing subjects per arm, the pharmacokineticsof clarithromycin, 14-hydroxyclarithromycin, rifabutin,25-O-desacetylrifabutin, and clofazimine data were assessed from thefollowing treatments:

Treatment A: Triple Combination Capsules (dry formulation)

Treatment B: Triple Combination Capsules (PEG formulation)

Pharmacokinetic Analysis of Clarithromycin:

The peak and systemic exposures of clarithromycin were ˜25% and ˜20%lower after the single oral dose of triple combination capsules (dryformulation) when compared to triple combination capsules (PEGformulation). Also, the statistical results indicated that the 90%confidence intervals of the geometric mean ratios (dry/PEG) forAUC_(0-t), AUC_(0-inf), and C_(max) were 47.58% to 135.69%, 48.33% to135.03%, and 46.57% to 120.88%, respectively.

A single dose of 250 mg of clarithromycin resulted in a C_(max) of780±250 ng/mL. The results obtained from dry and PEG formulations oftriple combination capsules were approximately proportional toliterature findings. Chu et al. (1993) reported that the rise ofclarithromycin peak concentrations occur non-linearly to dose whichmight explain any slight disproportionality between the literaturevalues and those obtained from triple combination capsules dry and PEGformulations.

There was however, no significant difference in the rate of exposure(T_(max)) of clarithromycin between the 2 formulations, indicating asimilar rate of absorption between the dry and PEG formulations (MedianT_(max) 4.00 hours). Similarly, the elimination half-life was also foundto be similar between the dry and PEG formulations (p value>0.05).

Pharmacokinetic Analysis of 14-Hydroxyclarithromycin:

The peak and systemic exposures of the metabolite,14-hydroxyclarithromycin were ˜12% and ˜7% lower after the single oraldose of triple combination capsules (dry formulation) when compared totriple combination capsules (PEG formulation). Also, the statisticalresults indicated that the 90% confidence intervals of the geometricmean (dry/PEG) for AUC_(0-t), AUC_(0-inf), and C_(max) were 65.11% to133.20%, 65.43% to 132.57%, and 61.72% to 125.43%, respectively.

Similar to the parent compound, there was no significant difference inthe rate of exposure (T_(max)) of 14-hydroxyclarithromycin between the 2formulations, indicating a similar rate of absorption between the dryand PEG formulations (Median T_(max) 4.00 hours). Similarly, theelimination half-life was also found to be similar between the dry andPEG formulations (p values>0.05).

Pharmacokinetic Analysis of Rifabutin:

The peak and systemic exposures of rifabutin were ˜11% and ˜23% lowerafter the single oral dose of triple combination capsules (dryformulation) when compared to triple combination capsules (PEGformulation). Also, the statistical results indicated that the 90%confidence intervals of the geometric mean ratios (dry/PEG) forAUC_(0-t), AUC_(0-inf), and C_(max) were 57.12% to 103.80%, 53.02% to101.13%, and 71.44% to 110.23%, respectively.

Gatti et al. (1998) conducted a comparative study of rifabutinabsorption and disposition in HIV-infected patients with or withoutwasting syndrome. They found that the C_(max) (peak concentration) was340±140 ng/ml, in 10 HIV patients without wasting syndrome after asingle 300 mg dose of rifabutin administered under fasting conditions.

There was however, no significant difference in the rate of exposure(T_(max)) of rifabutin between the 2 formulations, indicating a similarrate of absorption between the dry and PEG formulations (Median T_(max)6.00 hours). Similarly, the elimination half-life was also found to besimilar between the dry and PEG formulations (p values>0.05).

Pharmacokinetic Analysis of 25-O-Desacetylrifabutin:

The peak and systemic exposures of the metabolite25-O-desacetylrifabutin were ˜26% lower after the single oral dose oftriple combination capsules (dry formulation) when compared to triplecombination capsules (PEG formulation). Also, the statistical resultsindicated that the 90% confidence intervals of the geometric mean ratios(dry/PEG) for AUC_(0-t) and C_(max) were 55.19% and 97.71%,respectively. Approximately 65% of subjects were excluded from thestatistical analysis of AUC_(0-inf), K_(el), and t_(1/2) due to theAUC_(0-inf) extrapolation being more than 20%. Hence, thepharmacokinetic discussion was not based on the outcome of AUC_(0-inf).

Similar to the parent compound, there was no significant difference inthe rate of exposure (T_(max)) of 25-O-desacetylrifabutin between the 2formulations, indicating a similar rate of absorption between the dryand the PEG formulation (Median dry and PEG T_(max) 6.01 hours and 7.04hours, respectively). Similarly, the elimination half-life was alsofound to be similar between the dry and PEG formulations (pvalues>0.05).

Pharmacokinetic Analysis of Clofazimine:

The peak exposure of clofazimine was ˜19% (C_(max)) higher after thesingle oral dose of triple combination capsules (dry formulation) whencompared to triple combination capsules (PEG formulation). However, thetotal systemic exposure (AUC_(0-t)) was found to be similar between the2 formulations, with a geometric mean ratio of 102%. The statisticalresults indicated that the 90% confidence intervals of the geometricmean ratios (dry/PEG) for AUC_(0-t) and C_(max) were 66.12% to 158.52%,and 83.26% to 169.02%, respectively. Approximately 50% (Treatment A) and75% (Treatment B) of subjects were excluded from the statisticalanalysis of AUC_(0-inf), K_(el) and t_(1/2) due to the AUC_(0-inf)extrapolation being more than 20%. Hence, the pharmacokinetic discussionwas not based on the outcome of AUC_(0-inf).

Nix et al. (2004) reported proportional values after administration of a200 mg dose. The C_(max) was found to be 227 ng/mL. These values areproportional to the values obtained from administration of triplecombination capsules in the current study.

There was however, no significant difference in the rate of exposure (T)of clofazimine between the 2 formulations, indicating a similar rate ofabsorption between the dry and PEG formulations (Median T.sub.max 8.00hours). Similarly, the elimination half-life was also found to besimilar between the dry and PEG formulations (p values>0.05).

CONCLUSION

The relative bioavailability of clarithromycin, rifabutin, clofazimine,and their metabolites were assessed by measuring and comparing the peakand total systemic exposures from the 2 treatments (using AUC_(0-t),AUC_(0-inf), and C_(max)).

The dry/PEG geometric mean ratios of the total systemic exposures (AUCs)for clarithromycin, rifabutin and their metabolites were lower by˜7%-26%. Similarly, the dry/PEG geometric mean ratios of the peaksystemic exposures (C_(max)) for clarithromycin, rifabutin, and theirmetabolites were found to be ˜11%-26% lower when compared to the PEGformulation. However, the total systemic exposures for clofazimine(AUC_(0-t)) were similar between the dry formulation and the PEGformulation, The peak exposure of the dry formulation was ˜19% (C_(max))higher than that of the PEG formulation. There was no significantdifference in the time to peak concentration for any of the analytesfrom either the dry or the PEG formulation treatment group.

Overall, triple combination (dry and PEG formulations) were welltolerated as a single-dose of about 190 mg of clarithromycin, about 90mg of rifabutin, and about 20 mg of clofazimine, and no significantsafety issues emerged.

2 C_(max) Comparisons with Literature Values

Clofazimine—C_(max) fed=227 ng/ml after 200 mg dose (Nix, et al., 2004).

Triple combination (dry form) 38.32±20.98 ng/mL. Triple combination (PEGform). 29.82±11.37 ng/mL (Bioavailability study with 20 mg). 20 mg dosegives C_(max) of 23 ng/mL.

Rifabutin—C_(max) (peak concentration) was 340±140 ng/mL in 10 HIVpatients without wasting syndrome after a single 300-mg dose ofrifabutin administered fasting (Comparative study of rifabutinabsorption and disposition in HIV-infected patients with or withoutwasting syndrome. Gatti G, Di Biagio A, De Pascalis C, Guerra M,Bassetti M, Bassetti D. Int Conf AIDS. 1998; 12: 554 (abstract no.32171)).

Triple combination (dry form) 151.41±60.47 ng/mL. Triple combination(PEG Form) 166.39±44.37 ng/mL (Bioavailability study with 90 mg). 90 mgdose gives C_(max) of 102 ng/mL.

Clarithromycin—500 mg (four 125-mg capsules, Abbott Laboratories) every12 hours for 5 doses. C_(max) 2410±670 mg/L and 660±210 ng/mL formetabolite. Single dose of 250 mg resulted in C_(max) of 780±250 ng/mL.

Triple combination (dry form) 450.69±251.30, Triple Combination (PEGForm) 549.18±253.41 (Bioavailability study with 190 mg). 190 mg dosegives C_(max) of 593 ng/mL.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, numerous equivalents to thecompounds, compositions, and methods of use thereof described herein.Such equivalents are considered to be within the scope of the presentdisclosure and are covered by the following embodiments.

The contents of all references, patents and published patentapplications cited throughout this Application, as well as theirassociated figures are hereby incorporated by reference in theirentirety.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the scope of theinvention as broadly described. The present embodiments are, therefore,to be considered in all respects as illustrative and not restrictive.

What is claimed is:
 1. A pharmaceutical composition comprising a co-formulated fixed-dose combination comprising rifabutin, clarithromycin, and a clofazimine-polymer solid dispersion, wherein the co-formulated fixed-dose combination comprises 30-60 mg rifabutin, 65-125 mg clarithromycin and 4-16 mg clofazimine.
 2. The pharmaceutical composition of claim 1 wherein rifabutin is at a dose of 30 mg, clarithromycin is at a dose of 95 mg, and clofazimine is at a dose of 10 mg.
 3. The pharmaceutical composition of claim 1 wherein rifabutin is at a dose of 45 mg, clarithromycin is at a dose of 95 mg, and clofazimine is at a dose of 10 mg.
 4. The pharmaceutical composition of claim 1 wherein the fixed-dose composition is a tablet.
 5. The pharmaceutical composition of claim 1 wherein the fixed-dose composition is a capsule. 